1. Field of the Invention
The present invention relates to novel vinyl ester (VER) containing oxazolidone ring; and more specifically, the present invention relates to novel VER containing oxazolidone ring prepared from a) an epoxy resin; b) an adduct comprising at least one oxazolidone ring prepared from a multifunctional epoxy resin and an isocyanate compound; and c) an unsaturated acid, the process of manufacturing the VER, and compositions therefrom.
2. Description of Background
Vinyl ester products have been widely used for composite applications. High temperature resistance combined with high toughness is one of the key requirements in composite applications which require that the cured composites should have high Tg with wider processing window.
Oxazolidone-containing epoxy resins used to make VER are known. Epoxy-MDI adducts can react in the presence of a vinyl monomer solution with a specific catalysts such as ammonium or phosphonium salts. Another preferred variant of vinyl ester resins is obtained when oxazolidone group-containing polyepoxide resins from bisepoxides and diisocyanates are used as oligomeric epoxide resins. After reaction of these with methacrylic acid in styrene solution, they represent valuable vinyl ester resins also in the acidified form; they are characterized by high mechanical strength combined with high thermo-stability and hydrolysis resistance in the hardened state.
Additional compositions that are known include vinyl esters that bear one or more oxazolidone rings per molecule on average, and vinyl esters that have phosphorous atoms and one or more oxazolidone rings per molecule on average, which are prepared from bifunctional epoxy resins such as bisphenol A epoxy resins, bisphenol F epoxy resins, and bisphenol S epoxy resins. In an embodiment, the present invention provides vinyl ester made from oxazolidone containing multi-functional epoxy resins and it was showed that use of such multi-functional resins can increase the thermal resistance as well as the processing window (longer gel time).